A central government with its own currency can pay for its spending by creating money de novo, [3] but Government debt is generally generated to offset the deficit when spending exceeds receipts. This practice stems from a desire to impose discipline on government spending and to avoid hyperinflation.[citation needed]

As the government draws its income from much of the population, government debt is an indirect debt of the taxpayers. Government debt can be categorized as internal debt (owed to lenders within the country) and external debt (owed to foreign lenders). Another common division of government debt is by duration until repayment is due. Short term debt is generally considered to be for one year or less, long term is for more than ten years. Medium term debt falls between these two boundaries. A broader definition of government debt may consider all government liabilities, including future pension payments and payments for goods and services the government has contracted but not yet paid.

During the Early Modern era, European monarchs would often default on their loans or arbitrarily refuse to pay them back. This generally made financiers wary of lending to the king and the finances of countries that were often at war remained extremely volatile.

The creation of the first central bank in England – an institution designed to lend to the government – was initially an expedient by William III of England for the financing of his war against France. He engaged a syndicate of City traders and merchants to offer for sale an issue of government debt. This syndicate soon evolved into the Bank of England, eventually financing the wars of the Duke of Marlborough and later Imperial conquests.

The establishment of the bank was devised by Charles Montagu, 1st Earl of Halifax, in 1694, to the plan which had been proposed by William Paterson three years before, but had not been acted upon.[4] He proposed a loan of £1.2m to the government; in return the subscribers would be incorporated as The Governor and Company of the Bank of England with long-term banking privileges including the issue of notes. The Royal Charter was granted on 27 July through the passage of the Tonnage Act 1694.[5]

The founding of the Bank of England revolutionised public finance and put an end to defaults such as the Great Stop of the Exchequer of 1672, when Charles II had suspended payments on his bills. From then on, the British Government would never fail to repay its creditors.[6] In the following centuries, other countries in Europe and later around the world adopted similar financial institutions to manage their government debt.

1815, at the end of the Napoleonic Wars, British government debt reached a peak of more than 200% of GDP.[7]

Public debt as a percent of GDP, evolution for USA, Japan and the main EU economies.

Public debt as a percent of GDP by CIA

Government debt as a percent of GDP by IMF

A government bond is a bond issued by a national government. Such bonds are most often denominated in the country's domestic currency. Sovereigns can also issue debt in foreign currencies: almost 70% of all debt in 2000 was denominated in US dollars.[8] Government bonds are sometimes regarded as risk-free bonds, because national governments can if necessary create money de novo to redeem the bond in their own currency at maturity. Although many governments are prohibited by law from creating money directly (that function having been delegated to their central banks), central banks may provide finance by buying government bonds, sometimes referred to as monetizing the debt.

Government debt, synonymous to sovereign debt,[9] can be issued either in domestic or foreign currencies. Investors in sovereign bonds denominated in foreign currency have exchange rate risk: the foreign currency might depreciate against the investor's local currency. Sovereigns issuing debt denominated in a foreign currency may furthermore be unable to obtain that foreign currency to service debt. In the 2010 Greek debt crisis, for example, the debt is held by Greece in Euros, and one proposed solution (advanced notably by World Pensions Council (WPC) financial economists) is for Greece to go back to issuing its own drachma.[10][11] This proposal would only address future debt issuance, leaving substantial existing debts denominated in what would then be a foreign currency, potentially doubling their cost[12]

Public debt is the total of all borrowing of a government, minus repayments denominated in a country's home currency. CIA's World Factbook lists only the percentages of GDP; the total debt and per capita amounts have been calculated in the table below using the GDP (PPP) and population figures of the same report.

* US data exclude debt issued by individual US states, as well as intra-governmental debt; intra-governmental debt consists of Treasury borrowings from surpluses in the trusts for Federal Social Security, Federal Employees, Hospital Insurance (Medicare and Medicaid), Disability and Unemployment, and several other smaller trusts; if data for intra-government debt were added, "Gross Debt" would increase by about one-third of GDP. The debt of the United States over time is documented online at the Department of the Treasury's website TreasuryDirect.Gov[14] as well as current totals.[15]

Governments often borrow money in a currency in which the demand for debt securities is strong. An advantage of issuing bonds in a currency such as the US dollar, the pound sterling, or the euro is that many investors wish to invest in such bonds. Countries such as the United States, Germany, Italy and France have only issued in their domestic currency (or in the Euro in the case of Euro members).

Relatively few investors are willing to invest in currencies that do not have a long track record of stability. A disadvantage for a government issuing bonds in a foreign currency is that there is a risk that it will not be able to obtain the foreign currency to pay the interest or redeem the bonds. In 1997 and 1998, during the Asian financial crisis, this became a serious problem when many countries were unable to keep their exchange rate fixed due to speculative attacks.

Although a national government may choose to default for political reasons, lending to a national government in the country's own sovereign currency is generally considered "risk free" and is done at a so-called "risk-free interest rate." This is because the debt and interest can be repaid by raising tax receipts (either by economic growth or raising tax revenue), a reduction in spending, or by creating more money. However, it is widely considered that this would increase inflation and thus reduce the value of the invested capital (at least for debt not linked to inflation). This has happened many times throughout history, and a typical example of this is provided by Weimar Germany of the 1920s, which suffered from hyperinflation when the government massively printed money, because of its inability to pay the national debt deriving from the costs of World War I.[citation needed]

In practice, the market interest rate tends to be different for debts of different countries. An example is in borrowing by different European Union countries denominated in euros. Even though the currency is the same in each case, the yield required by the market is higher for some countries' debt than for others. This reflects the views of the market on the relative solvency of the various countries and the likelihood that the debt will be repaid. Further, there are historical examples where countries defaulted, i.e., refused to pay their debts, even when they had the ability of paying it with printed money. This is because printing money has other effects that the government may see as more problematic than defaulting.

A politically unstable state is anything but risk-free as it may—being sovereign—cease its payments. Examples of this phenomenon include Spain in the 16th and 17th centuries, which nullified its government debt seven times during a century, and revolutionary Russia of 1917 which refused to accept the responsibility for Imperial Russia's foreign debt.[17] Another political risk is caused by external threats. It is mostly uncommon for invaders to accept responsibility for the national debt of the annexed state or that of an organization it considered as rebels. For example, all borrowings by the Confederate States of America were left unpaid after the American Civil War. On the other hand, in the modern era, the transition from dictatorship and illegitimate governments to democracy does not automatically free the country of the debt contracted by the former government. Today's highly developed global credit markets would be less likely to lend to a country that negated its previous debt, or might require punishing levels of interest rates that would be unacceptable to the borrower.

U.S. Treasury bonds denominated in U.S. dollars are often considered "risk free" in the U.S. This disregards the risk to foreign purchasers of depreciation in the dollar relative to the lender's currency. In addition, a risk-free status implicitly assumes the stability of the US government and its ability to continue repayments during any financial crisis.

Lending to a national government in a currency other than its own does not give the same confidence in the ability to repay, but this may be offset by reducing the exchange rate risk to foreign lenders. On the other hand, national debt in foreign currency cannot be disposed of by starting a hyperinflation;[citation needed] and this increases the credibility of the debtor. Usually small states with volatile economies have most of their national debt in foreign currency. For countries in the Eurozone, the euro is the local currency, although no single state can trigger inflation by creating more currency.

Lending to a local or municipal government can be just as risky as a loan to a private company, unless the local or municipal government has sufficient power to tax. In this case, the local government could to a certain extent pay its debts by increasing the taxes, or reduce spending, just as a national one could. Further, local government loans are sometimes guaranteed by the national government, and this reduces the risk. In some jurisdictions, interest earned on local or municipal bonds is tax-exempt income, which can be an important consideration for the wealthy.

Public debt clearing standards are set by the Bank for International Settlements, but defaults are governed by extremely complex laws which vary from jurisdiction to jurisdiction. Globally, the International Monetary Fund can take certain steps to intervene to prevent anticipated defaults. It is sometimes criticized for the measures it advises nations to take, which often involve cutting back on government spending as part of an economic austerity regime. In triple bottom line analysis, this can be seen as degrading capital on which the nation's economy ultimately depends.

Those considerations do not apply to private debts, by contrast: credit risk (or the consumer credit rating) determines the interest rate, more or less, and entities go bankrupt if they fail to repay. Governments need a far more complex way of managing defaults because they cannot really go bankrupt (and suddenly stop providing services to citizens), albeit in some cases a government may disappear as it happened in Somalia or as it may happen in cases of occupied countries where the occupier doesn't recognize the occupied country's debts.

Smaller jurisdictions, such as cities, are usually guaranteed by their regional or national levels of government. When New York City declined into what would have been a bankrupt status during the 1970s (had it been a private entity), by the mid-1970s a "bailout" was required from New York State and the United States. In general, such measures amount to merging the smaller entity's debt into that of the larger entity and thereby giving it access to the lower interest rates the larger entity enjoys. The larger entity may then assume some agreed-upon oversight in order to prevent recurrence of the problem.

According to Modern Monetary Theory, public debt is seen as private wealth and interest payments on the debt as private income. The outstanding public debt is an expression of the accumulated previous budget deficits which have added financial assets to the private sector, providing demand for goods and services. Adherents of this school of economic thought argue that the scale of the problem is much less severe than is popularly supposed.[18]

Wolfgang Stützel showed with his Saldenmechanik (Balances Mechanics) how a comprehensive debt redemption would compulsorily force a corresponding indebtedness of the private sector, due to a negative Keynes-multiplier leading to crisis and deflation.[19]

In the dominant economic policy generally ascribed to theories of John Maynard Keynes, sometimes called Keynesian economics, there is tolerance for fairly high levels of public debt to pay for public investment in lean times, which, if boom times follow, can then be paid back from rising tax revenues. Empirically, however, sovereign borrowing in developing countries is procyclical, since developing countries have more difficulty accessing capital markets in lean times.[20]

As this theory gained global popularity in the 1930s, many nations took on public debt to finance large infrastructural capital projects—such as highways or large hydroelectric dams. It was thought that this could start a virtuous cycle and a rising business confidence since there would be more workers with money to spend. Some[who?] have argued that the greatly increased military spending of World War II really ended the Great Depression. Of course, military expenditures are based upon the same tax (or debt) and spend fundamentals as the rest of the national budget, so this argument does little to undermine Keynesian theory. Indeed, some[who?] have suggested that significantly higher national spending necessitated by war essentially confirms the basic Keynesian analysis (see Military Keynesianism).

Understanding the structure of public debt and analyzing its risk requires one to:

Assess the expected value of any public asset being constructed, at least in future tax terms if not in direct revenues. A choice must be made about its status as a public good—some public "assets" end up as public bads, such as nuclear power plants which are extremely expensive to decommission—these costs must also be worked into asset values.

Determine whether triple bottom line issues are likely to lead to failure or defaults of governments—say due to being overthrown.

Determine whether any of the debt being undertaken may be held to be odious debt, which might permit it to be disavowed without any effect on a country's credit status. This includes any loans to purchase "assets" such as leaders' palaces, or the people's suppression or extermination. International law does not permit people to be held responsible for such debts—as they did not benefit in any way from the spending and had no control over it.

Determine if any future entitlements are being created by expenditures—financing a public swimming pool for instance may create some right to recreation where it did not previously exist, by precedent and expectations.

Not all developing countries have been affected to the same extent. For example, Yugoslavia had low government debt (perhaps because it was unable to borrow on world markets)[citation needed] until its breakup and the coming of democracy, when the new national governments started to borrow money from the IMF. Croatia has a government debt of $47 billion today while the whole of Yugoslavia (six times as many people as Croatia) in 1980 had debt of $14 billion.[citation needed]

Government "implicit" debt is the promise by a government of future payments from the state. Usually this refers to long term promises of social payments such as pensions and health expenditure; not promises of other expenditure such as education or defense (which are largely paid on a "quid pro quo" basis to government employees and contractors).

In the United States, as in most other countries, there is no money earmarked in the government's coffers for future social insurance payments. This insurance system is called PAYGO (pay-as-you-go). Alternative social insurance strategies might have included a system that involved save and invest.

Furthermore, population projections predict that when the "baby boomers" start to retire, the working population in the United States, and in many other countries, will be a smaller percentage of the population than it is now, for many years to come. This will increase the burden on the country of these promised pension and other payments—larger than the 65 percent[21] of GDP that it is now. The "burden" of the government is what it spends, since it can only pay its bills through taxes, debt, and increasing the money supply (government spending = tax revenues + change in government debt held by public + change in monetary base held by the public). "Government social benefits" paid by the United States government during 2003 totaled $1.3 trillion.[22]

In 2010 the European Commission required EU Member Countries to publish their debt information in standardized methodology, explicitly including debts that were previously hidden in a number of ways to satisfy minimum requirements on local (national) and European (Stability and Growth Pact) level.[23]

^Committee of Finance and Industry 1931 (Macmillan Report) description of the founding of Bank of England. Books.google.ca. Retrieved 10 May 2010. "Its foundation in 1694 arose out the difficulties of the Government of the day in securing subscriptions to State loans. Its primary purpose was to raise and lend money to the State and in consideration of this service it received under its Charter and various Act of Parliament, certain privileges of issuing bank notes. The corporation commenced, with an assured life of twelve years after which the Government had the right to annul its Charter on giving one year's notice. '''Subsequent extensions of this period coincided generally with the grant of additional loans to the State'''"